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Decoherence as a probe of coherent quantum dynamics.
Michael B D'Arcy1, Rachel M Godun, Gil S Summy
1Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom.
Summary
Weak decoherence from spontaneous emission minimally impacts cold atom energy growth but significantly alters momentum distributions. This explains the observed enhancement of resonances, clarifying decoherence
Area of Science:
- Atomic physics
- Quantum dynamics
- Optical lattices
Background:
- Cold atoms in optical lattices exhibit complex dynamics under periodic driving.
- Spontaneous emission introduces decoherence, affecting quantum system evolution.
- Previous observations showed an unexplained enhancement of resonances by decoherence.
Purpose of the Study:
- To experimentally and theoretically investigate the effect of decoherence on cold atom dynamics.
- To understand how spontaneous emission influences energy growth and momentum distributions.
- To resolve the puzzle of decoherence-induced resonance enhancement.
Main Methods:
- Experimental study of cold atoms subjected to a kicked optical lattice.
- Theoretical modeling of decoherence effects, specifically spontaneous emission.
- Analysis of mean energy growth and resonant momentum distributions.
Main Results:
- Weak decoherence has a negligible effect on the mean energy growth of cold atoms.
- Decoherence fundamentally alters resonant momentum distributions.
- Experimental sensitivity to specific features of these distributions explains resonance enhancement.
Conclusions:
- Decoherence's impact is primarily on the detailed structure of momentum distributions, not overall energy.
- The study clarifies the interplay between coherent evolution and decoherence in kicked atomic systems.
- The findings resolve a long-standing puzzle regarding decoherence-enhanced resonances.